[clang] [analyzer][NFC] Make CheckerDocumentation checker in-sync with actual checker callbacks (PR #83973)

[Balazs Benics via cfe-commits]

https://github.com/steakhal created https://github.com/llvm/llvm-project/pull/83973

In PR #83677 I was surprised to see that outdated checker callback signatures are a problem. It turns out, we need the `registerChecker...` function to invoke the `Mgr.registerChecker<>()` which would instantiate the `_register` calls, that would take the address of the defined checker callbacks. Consequently, if the expected signatires mismatch, it won't complie from now on, so we have static guarantee that this issue never pops up again.

Given we need the `register` call, at this point we could just hook this checker into the `debug` package and make it never registered. It shouldn't hurt anyone :)

>From 8d6e6fe68663d9788a994a214c8f29c5f4e2a958 Mon Sep 17 00:00:00 2001
From: Balazs Benics <benicsbalazs at gmail.com>
Date: Tue, 5 Mar 2024 09:29:19 +0100
Subject: [PATCH] [analyzer][NFC] Make CheckerDocumentation checker in-sync
 with actual checker callbacks

In PR #83677 I was surprised to see that outdated checker callback
signatures are a problem. It turns out, we need the `registerChecker...`
function to invoke the `Mgr.registerChecker<>()` which would instantiate
the `_register` calls, that would take the address of the defined
checker callbacks. Consequently, if the expected signatires mismatch, it
won't complie from now on, so we have static guarantee that this issue
never pops up again.

Given we need the `register` call, at this point we could just hook this
checker into the `debug` package and make it never registered.
It shouldn't hurt anyone :)
---
 .../clang/StaticAnalyzer/Checkers/Checkers.td       |  4 ++++
 .../Checkers/CheckerDocumentation.cpp               | 13 +++++++++----
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/clang/include/clang/StaticAnalyzer/Checkers/Checkers.td b/clang/include/clang/StaticAnalyzer/Checkers/Checkers.td
index a224b81c33a624..686e5e99f4a62c 100644
--- a/clang/include/clang/StaticAnalyzer/Checkers/Checkers.td
+++ b/clang/include/clang/StaticAnalyzer/Checkers/Checkers.td
@@ -1654,6 +1654,10 @@ def StdCLibraryFunctionsTesterChecker : Checker<"StdCLibraryFunctionsTester">,
   WeakDependencies<[StdCLibraryFunctionsChecker]>,
   Documentation<NotDocumented>;
 
+def CheckerDocumentationChecker : Checker<"CheckerDocumentation">,
+  HelpText<"Defines an empty checker callback for all possible handlers.">,
+  Documentation<NotDocumented>;
+
 } // end "debug"
 
 
diff --git a/clang/lib/StaticAnalyzer/Checkers/CheckerDocumentation.cpp b/clang/lib/StaticAnalyzer/Checkers/CheckerDocumentation.cpp
index 0ca0c487b64550..01e0bed54cc6ed 100644
--- a/clang/lib/StaticAnalyzer/Checkers/CheckerDocumentation.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/CheckerDocumentation.cpp
@@ -137,10 +137,7 @@ class CheckerDocumentation : public Checker< check::PreStmt<ReturnStmt>,
   /// (2) and (3). Post-call for the allocator is called after step (1).
   /// Pre-statement for the new-expression is called on step (4) when the value
   /// of the expression is evaluated.
-  /// \param NE     The C++ new-expression that triggered the allocation.
-  /// \param Target The allocated region, casted to the class type.
-  void checkNewAllocator(const CXXNewExpr *NE, SVal Target,
-                         CheckerContext &) const {}
+  void checkNewAllocator(const CXXAllocatorCall &, CheckerContext &) const {}
 
   /// Called on a load from and a store to a location.
   ///
@@ -330,5 +327,13 @@ void CheckerDocumentation::checkPostStmt(const DeclStmt *DS,
                                          CheckerContext &C) const {
 }
 
+void registerCheckerDocumentationChecker(CheckerManager &Mgr) {
+  Mgr.registerChecker<CheckerDocumentation>();
+}
+
+bool shouldRegisterCheckerDocumentationChecker(const CheckerManager &) {
+  return false;
+}
+
 } // end namespace ento
 } // end namespace clang